¼ cup finely diced white or yellow onion (you need about ⅓ of a small onion for that), 1 teaspoon dried oregano, 1 teaspoon smoked hot paprika, 1 ounce grated cheddar cheese (about ¼ cup)
Stir in the sausage meat.
Stuff the filling into the mushroom caps using either a firm rubber spatula or a spoon. Set the stuffed mushrooms (stuffed side up) onto a baking sheet lined with aluminum foil.
Bake uncovered until the mushrooms are soft and the filling is starting to brown (about 30 minutes). Serve hot.
Recipe notes:
*Please don't use any cream cheese products labeled low-fat or reduced-fat. Those have a higher moisture content than full-fat cream cheese and that can keep them from melting properly.Make ahead instructions: You can make the filling and stuff the mushrooms up to 6 hours ahead. Keep them in an airtight container in the fridge until you're ready to bake them.